This invention relates to a colored lens used for glasses or the like, and more particularly to, a method of designing a colored lens enabling a user thereof to identify the colors of objects as equally as in naked eye view.
A lens to be mounted on glasses and sunglasses is dyed with iodine or dye to be colored in order to protect pupils from sunlight or intense illumination.
Light that has passed through such a colored lens contains a large amount of colors of a colorant, thereby producing a different color from the one felt directly with the naked eye. Therefore, there is a problem in that it is difficult to recognize the color of the light that has passed through the colored lens as the same color as perceived with the naked eye. Specifically, there are problems, such as the inability to compare the maturity of a fruit with a color sample in a fruit farm, to distinguish between aquarium fish, or to identify colors when drawing a picture outside.
Meanwhile, according to JP H10-133016 A, there is disclosed a technology for providing a polarized lens enabling the user thereof to distinguish colors as positively as with the naked eye within the ranges of 22≦L≦70, −2.0≦a≦2.0, and −2.0≦b≦2.0 in a uniform color space.
However, the related art specifies both an a-value and a b-value within the same rectangle for all kinds of L-values (brightness), which means that those values do not match actual conditions. Further, in the related art, the ranges of the a-value and the b-value are narrow, and hence in the case where a lens, which enables the user thereof to identify the colors of objects as equally as in naked eye view, is to be provided, it is difficult to realize the tint (light reflected by the lens, i.e., the color appearance of the lens) of the lens that satisfies the user's request for colors. Further, the polarized lens in the related art employs a polarizing film that is neither colorless nor transparent. Accordingly, the colored lens that does not have polarization characteristics and the polarized lens need different ideas to set a condition of colors for enabling the user thereof to identify the colors of objects as equally as in naked eye view.
Regarding a colored lens that does not have polarization characteristics, it is an object of this invention to provide a colored lens enabling the user thereof to identify the colors of objects as equally as in naked eye view.